Washerless dishwasher basket wheel assembly

ABSTRACT

A washerless dishwasher basket wheel assembly that uses a countersunk sprocket opening in the sprocket of the wheel through which a shoulder screw having raised retaining nibs formed thereon is retaining connected there. The nibs extend radially outwardly of the opening of the sprocket to retain the screw connection to the wheel and, normally, to prevent its removal therefrom.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation application of pending PCT International Application PCT/US02/06780 which was filed in the U.S. Receiving Office on Mar. 6, 2002 and published on Oct. 10, 2002 as WO 02/078497 Al. PCT International Application PCT/US02/06780 claims the benefit of U.S. Provisional Application No. 60/279,571, filed Mar. 29, 2001. The disclosure of the above applications is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to a dishwasher basket wheel assembly and, in particular, to an improved dishwasher basket wheel assembly.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] The prior art dishwasher basket wheel assembly used a plastic wheel through which a shoulder screw having a knurled end to which a washer was press filled to retain the screw on the wheel. The prior art shoulder screw had to have the end of the shoulder section knurled. Additionally, a washer had to be used. Lastly, the washer had to be pressed upon the knurled section to connect it to the screw and, thus, retain the screw on the wheel through the use of a hydraulic press.

[0004] Accordingly, it is a primary object of the present invention to provide a washerless dishwasher basket wheel assembly so as to eliminate the necessity of having a washer in the assembly.

[0005] Another object of the present invention is to use a plurality of raised retaining nibs at the end of the should and, thus, eliminate the knurled section at the end of the shoulder and the washer press fitted thereto. This also eliminates the requirement of a hydraulic press as there is no washer to act on.

[0006] In addition, it is an object of the present invention to provide a washerless dishwasher basket wheel assembly of the above described type that is inexpensive to manufacture, reliable and simple to install.

[0007] Furthermore, it is an object of the present invention to provide a washerless dishwasher basket wheel assembly adapted to be easily and securely assembled so that the assembly may be connect in the dishwasher in the conventional manner (i.e., in the same way prior art assemblies were connected in the dishwasher).

[0008] The washerless dishwasher basket wheel assembly of the present invention accomplishes these objectives by providing raised retaining nibs at the end of the shoulder of the shoulder screw that is mounted in and connected to the sprocket of the wheel within the countersunk sprocket opening. The raised retaining nibs are designed to allow the screw to be pushed through the sprocket opening and to be snapped in place. The nibs define raised areas that act to retain the screw within the sprocket of the wheel and prevent it from accidentally being disconnected from the wheel, while permitting conventional easy installation of the said assembly into the dishwasher. Furthermore, the countersink in the sprocket opening provides a clearance area within the sprocket of the wheel so that the wheel can freely rotate relative the shoulder screw without interference or binding of, by or between the raised retaining nibs and the sprocketed opening of the wheel.

[0009] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, wherein:

[0011]FIG. 1 is a side elevational view, partly in section, of a prior art dishwasher basket wheel assembly;

[0012]FIG. 2 is an exploded perspective view of the present invention;

[0013]FIGS. 3a through 3 c are side sectional views, partly in section, of the present invention;

[0014]FIG. 4 is a view, slightly enlarged, taken along line 4-4 of FIG. 3;

[0015]FIG. 5 is a similar view as shown in FIG. 4, except that the number of raised retaining nibs therein have been increased (i.e., from four nibs in FIG. 4 to eight nibs in FIG. 5);

[0016]FIGS. 6a and 6 b are views of another embodiment of the present invention;

[0017]FIG. 7 is an exploded perspective view of another embodiment of the present invention; and

[0018]FIGS. 8a and 8 b represent an exploded perspective view of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0020] With reference to the accompanying drawings, FIG. 1 shows a conventional dishwasher basket wheel assembly 10. A plastic or other suitable material wheel 12 is assembled with a shoulder screw 14 which is retained thereto by a plain flat washer 16 that is force-fitted by a suitable hydraulic press (not shown) onto a knurl 18 formed on the outer end of a shoulder 20 adjacent a threaded section 22 with an enlarged head 24 formed at the end of the shoulder 20 remote from the knurl 18. The wheel 12 has a sprocket or hub 26 having an opening 28 through which the shoulder screw 14 is disposed with the head 24 in superposition below a pair of wheel rims 30, 30 formed on opposite sides of a rail guideway 32. The function of the washer 16 is to retain the assembly 10 of the screw 14 from the wheel 12. Of course, once the assembly 10 is installed into a dishwasher (not shown), the washer 16 would no longer be required.

[0021] Turning now to the first embodiment of the invention which is shown in FIGS. 2, 3 and 4, like components, as shown and described in FIG. 1, will be given the same reference characters, while different components will be described and given new reference characters.

[0022] One of the main advantages of the present invention, as shown in FIGS. 2, 3 and 4, is the elimination of a washer to complete the assembly 10 and the advantages that flow from this, such as lowering the cost by simplifying the assembly 10, eliminating the washer and the knurling operation and no longer requiring the use of a hydraulic press to force-fit the washer upon the knurl of the shoulder screw. Accordingly, as shown in FIGS. 2, 3 and 4, the wheel 12 has a pair of rims 30 formed on opposite sides of the rail guideway 32 formed radially outwardly of a sprocket or hub 26 through which extends an opening 28 that is countersunk at 34, as best shown in FIG. 3, on the proximal end 27 of the opening 28 extending inwardly a short distance from the end 36 thereof. The shoulder screw or fastener 14 has an enlarged head 24 at an end thereof and a threaded section 22 at the other end. A plurality of raised retaining nibs 38, four in number in the preferred embodiment of the invention, though any number could be used so long as they extend radially outwardly of the opening 28 so as normally to prevent the removal of the screw 14 from the wheel 12.

[0023]FIG. 2 shows the wheel 12 and the screw 14 unassembled. FIG. 3 shows an assembled view of the preferred embodiment of the invention. The tolerances of the interfitted components may be varied, but in the preferred embodiment shown in FIGS. 2, 3 and 4, the desired range of sizes is as follows: for shoulder 20 of the screw 14, the range of diameters is between 0.248″ to 0.250″; the range of diameters between oppositely disposed pairs of the raised retaining nibs 38, 38 is between 0.265″ to 0.270″ which establishes a range of sizes for each of the raised retaining nibs 38 between an minimum radial height of 0.005″ and a maximum total height of 0.025″. The diameter of the opening 28 of the sprocket 26 will be sized to accommodate the shoulder screw 14 and permit the shoulder screw 14 to be inserted therein under suitable light pressure.

[0024] The wheel 12 is of a plastic material that has a yieldable, resilient quality, so once the shoulder screw 14 has been inserted through the opening 28, the diameter of the opening resumes its original dimension, with a diameter which is smaller than the minimum—maximum diameter for the opposed pairs of raised retaining nibs 38, 38, but is slightly smaller than the diameter of the shoulder 20 permit free relative rotation therebetween. In other words, the shoulder screw 14 is placed therein so that the raised retaining nibs 38 are placed at the end of the opening 28 opposite the proximal end 36 thereof. The size of the raised retaining nibs 38 have been designed to allow the shoulder screw 14 to be pushed into the distal end 35 through the opening 28 of the sprocket 26 under light pressure to be snapped into assembled position. Also, the raised retaining nibs 38 have been sized to not only permit easy installation of the screw 14 into the wheel 12, but normally to prevent the shoulder screw 14 failing out or accidentally being removed from the wheel 12. Lastly, the countersink 34 provides a clearance area which may be molded into the wheel 12 so as to prevent the raised retaining nibs 38 from interfering with the rotation of the wheel 12.

[0025] As best seen in FIGS. 3b and 3 c, defined between the threaded portion 22 and the shoulder 20 of the shoulder screw 14 is a conical taper 21. The conical taper 21 functions to assist in elastically deforming the opening 28, while the threaded shoulder screw 14 is being inserted. FIG. 3c depicts the relaxation of the opening 28 to its original diameter after the shoulder screw 14 is inserted. Further shown is the relationship of the retaining nibs 38 to the hole 28 as well as the countersink 34.

[0026]FIG. 5 shows a second embodiment of the invention in which there are eight raised retaining nibs 38, one every 45° around the circumference, rather than four raised retaining nibs 38 at 90° each, as shown in FIG. 4. Other than that difference, everything else may be the same so that the same reference characters have been used for both the first embodiment and the second embodiment and the description of the second embodiment will not be separately described; rather, reference may be made to the description for the first embodiment which was set forth above.

[0027]FIGS. 6a and 6 b show a third embodiment to the present invention, in which there is a circular raised retainer 40 defined on the shoulder 20 of a shoulder screw 14. The shoulder screw 14 is placed within opening 28 so that the raised retainer 40 is placed through the distal end 35 of opening 28. The size of the raised retainer 40 is configured to allow the shoulder screw 14 to be pushed into the distal end 35 and through the opening 28. After passing through the opening 28, the raised retainer 40 is placed within the countersink area 34. The countersink area 34 defines a positive surface 37, which prevents extraction of the shoulder screw 14 from the hole 28.

[0028] As is best seen in FIG. 6b, disposed between the raised retainer 40 and the threads 22 is the conical taper 21. The conical taper 21 functions to displace the polymer material defining hole 28 within the sprocket 26. The outer diameter of the raised retainer 40 is preferably smaller than the inner diameter of the countersink area 34. It is envisioned that the hole 28 can take numerous profiles including, but not limited to, conical tapers defined in the proximal 36 and distal ends 35 of hole 28. It is important, however, that the internal topography of the hole 28 allow smooth and stable rotation of the wheel 12 about the shoulder screw 14.

[0029]FIG. 7 represents an alternate embodiment of the present invention. A plastic wheel 12 is assembled with the shoulder screw 14, which is retained to the wheel 12 by a plain flat washer 16. The washer 16 is press fit by a hydraulic press onto an intermediate portion 46 defined on a shoulder screw 14. The intermediate portion 46 has a diameter smaller than the diameter of the shoulder 20, yet larger than the diameter of the threaded portion 22. Additionally, the intermediate portion 46 has three or more raised retaining ribs 48 which span the length of the intermediate portion and are coupled to the interior diameter of the washer 16 via an interference fit.

[0030] The system represented in FIG. 7 is inserted within the hole 28 without elastically deforming the plastic of the sprocket 26. The washer 16 is configured to prevent the translation of the shoulder screw 14 within the hole.

[0031]FIGS. 8a and 8 b depict yet another embodiment of the present invention. As best seen in FIG. 8a, the shoulder screw 14 defines a tapered conical head portion 48, and a medial stop 50. The conical tapered head portion 48 is pressed through the bore 28 of the wheel 12. Medial stop 50 functions to prevent the shoulder screw 14 from being inserted too far into the hole 28 while allowing proper rotation of the wheel 12 about the shoulder screw 14.

[0032] As best seen in FIG. 8b, the plastic of the hole 28 relaxes to conform about the shoulder portion 20 of shoulder screw 14. Stop 50 can be configured to have a diameter which would allow it to rest within the countersink 34 or, likewise, can have a diameter larger so that it functions to interact with the proximal end of the wheel 12.

[0033] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

What is claimed is:
 1. A wheel assembly comprising: a fastener having a shoulder portion having a first diameter, an intermediate portion having a second diameter which is less than said first diameter and a threaded portion, said intermediate portion being interposed between said shoulder portion and said threaded portion and having a plurality of raised longitudinal ribs extending radially outwardly therefrom; a wheel defining a hole therethrough receiving said fastener such that said shoulder portion supports said wheel for rotation thereon; and a washer defining an aperture formed therethrough received over said intermediate portion such that said plurality of raised longitudinal ribs secure said washer to said fastener.
 2. The wheel assembly according to claim 1 wherein the intermediate portion has a length and wherein the raised ribs extend the length of the intermediate portion.
 3. The wheel assembly according to claim 1 wherein the raised ribs define an exterior radius greater than the inner diameter of the washer.
 4. The wheel assembly according to claim 1 having more than three raised ribs.
 5. The wheel assembly according to claim 1 wherein the raised ribs are coupled to the aperture via an interference fit.
 6. The wheel assembly according to claim 1 wherein the threaded portion has a third exterior radius, said third exterior radius being less than the second radius.
 7. A kit for a wheel assembly comprising: a fastener having a shoulder portion having a first diameter, an intermediate portion having a second diameter which is less than said first diameter and a threaded portion and, said intermediate portion being interposed between said shoulder portion and said threaded portion and having a plurality of raised longitudinal ribs extending radially outwardly therefrom; a wheel defining a hole therethrough configured to receive said fastener such that said shoulder portion supports said wheel for rotation thereon; a washer having an aperture therethrough configured to receive said intermediate portion such that said plurality of raised longitudinal ribs secure said washer to said fastener.
 8. A method of coupling a wheel assembly to a dishwasher basket comprising: providing a fastener having a shoulder portion having a first diameter, an intermediate portion having a second diameter which is less than said first diameter and a threaded portion, said intermediate portion being interposed between said shoulder portion and said threaded portion and having a plurality of raised longitudinal ribs extending radially outwardly therefrom; disposing a wheel defining a hole therethrough about said shoulder portion thereby supporting said wheel for rotation thereon; disposing a washer having an aperture therethrough over said intermediate portion such that said plurality of raised longitudinal ribs secure said washer to said fastener; and coupling the fastener to the dishwasher basket. 